TY - THES

T1 - Modelling and Simulation of Foam-Assisted Water-Alternating-Gas Injection in Naturally Fractured Carbonate Reservoirs

AU - Gugl, Ronald

N1 - embargoed until null

PY - 2020

Y1 - 2020

N2 - In this research, carbonate core flooding experimental results of three different EOR methods were replicated numerically using CMG to study the enhancement of oil recovery in the gas invaded zone of carbonate fractured reservoirs. Experimental results for carbon dioxide injection, Water-alternating-gas injection [WAG], and foam-assisted water-alternating-gas injection [FAWAG] that were conducted in Iranian low-temperature fractured carbonate cores under both secondary and tertiary recovery conditions were used for this purpose. From these experiments, the relative permeability curves of the cores and the fitting foam parameters were derived using CMG. These findings were then used in a pilot model, that consists of a quarter five-spot pattern, and in a sector model where a double five-spot setup was used as the primary method of oil extraction. Additionally, all these models were first simulated, having been saturated by live-oil and connate water and secondly with a present gas invaded zone of 40% consisting out of methane. The foam-assisted recovery process was found to be a very useful aid in the recovery of gas invaded fractured reservoirs increasing the recovery factor in the pilot model by an astonishing twenty percent and in the sector model by more than two percent. By tuning the ratio of injected water and gas the recovery can be raised to as far as 7% additional recovery after 1 PVI for a tertiary stage.

AB - In this research, carbonate core flooding experimental results of three different EOR methods were replicated numerically using CMG to study the enhancement of oil recovery in the gas invaded zone of carbonate fractured reservoirs. Experimental results for carbon dioxide injection, Water-alternating-gas injection [WAG], and foam-assisted water-alternating-gas injection [FAWAG] that were conducted in Iranian low-temperature fractured carbonate cores under both secondary and tertiary recovery conditions were used for this purpose. From these experiments, the relative permeability curves of the cores and the fitting foam parameters were derived using CMG. These findings were then used in a pilot model, that consists of a quarter five-spot pattern, and in a sector model where a double five-spot setup was used as the primary method of oil extraction. Additionally, all these models were first simulated, having been saturated by live-oil and connate water and secondly with a present gas invaded zone of 40% consisting out of methane. The foam-assisted recovery process was found to be a very useful aid in the recovery of gas invaded fractured reservoirs increasing the recovery factor in the pilot model by an astonishing twenty percent and in the sector model by more than two percent. By tuning the ratio of injected water and gas the recovery can be raised to as far as 7% additional recovery after 1 PVI for a tertiary stage.

KW - EOR

KW - WAG

KW - FAWAG

KW - gas invaded zone

KW - simulation

KW - CMG

KW - GEM

KW - enhanced oil recovery

KW - foam

KW - gas mobility

KW - foam

KW - FAWAG

KW - WAG

KW - CO2

KW - core flooding

KW - sector

KW - EOR

KW - gas invaded zone

KW - simulation

KW - CMG

KW - GEM

KW - enhanced oil recovery

KW - gas mobility

M3 - Master's Thesis

ER -